Arrangement for switching rectified alternating current

Abstract

A rectifier has a d.c. return terminal and two d.c. output terminals. The elements of the rectifier are connected so that d.c. currents through the output terminals are discontinuous and that the sum of these currents is continuous d.c. output. Switches are provided to connect the d.c. output terminals to a common supply terminal for a load, or to isolate the output termnals from each other and from the load.

I claim: 
     
       1. An arrangement for switching rectified alternating current, comprising a rectifier arrangement having input terminals for an a.c. input and first and second terminals for direct current, said rectifier arrangement has a third direct current terminal and comprises rectifier elements connected so that first and second currents flowing through said second and third terminals respectively are discontinuous and that the sum of said first and second currents can provide a substantially continuous rectified output, and switch means operable between a first state in which said second and third terminals are commonly connected to a supply terminal for a load and a second state in which said second and third terminals are isolated from each other and from said supply terminal. 
     
     
       2. An arrangement as claimed in claim 1 in which said switch means provides a shunt for said load when operated in said second state. 
     
     
       3. An arrangement as claimed in claim 1 or claim 2 in which the number of phases of said a.c. input is odd and not less than three, the currents flowing through each of said second and third terminals being derived from 1+(n-1)/2 of the phases of said input, only one of said input phases being used to derive both input currents. 
     
     
       4. An arrangement as claimed in claim 1 or claim 2 in which the number of said phases is even and the currents flowing through said second and third terminals are derived from respective halves of said number of phases. 
     
     
       5. An arrangement as claimed in claim 1 or claim 2 in which said a.c. input is single phase and the currents flowing through said second and third terminals are derived from respective positive-going and negative-going half waves of said a.c. input.